北淮阳东段杨家湾岩体地球化学特征、锆石U-Pb定年及地质意义  

Geochemical characteristics and zircon U-Pb dating of the Yangjiawan pluton in the eastern part of North Huaiyang and their geological significances

作　　者：邱军强[1,2] 彭智[1] 陈芳[1,2] 董婷婷[1,2] 柳丙全[1] 

机构地区：[1]安徽省地质调查院,合肥230001 [2]安徽省大陆成矿研究中心,合肥230001

出　　处：《华东地质》2016年第2期89-96,共8页East China Geology

基　　金：中国地质调查局地质调查项目"安徽北淮阳地区成矿规律与资源潜力调查"(项目编号:1212011220547)资助

摘　　要：北淮阳东段杨家湾岩体为石英闪长岩,SiO_2、Al_2O_3和碱质含量中等,Mg#小,具准铝质高钾钙碱性系列岩石特征。该岩体的稀土元素含量较低,(La/Yb)N和LREE/HREE比值均较高,具较弱的Ce负异常,轻稀土分馏明显,重稀土较平坦,属轻稀土富集型;富集大离子亲石元素(LILE)Rb、Ba、K及高场强元素(HFSE)Zr、Hf、YNb、Ta、Ti、P、U呈低谷负异常,亏损HFSE,富集LILE。通过LA-ICP-MS锆石U-Pb定年,首次获得杨家湾岩体年龄为139.6±2.2Ma,属燕山中期,是早白垩世早期岩浆活动的产物,代表杨家湾岩体的成岩年龄。The Yangjiawan pluton in the eastern part of North Huaiyang,which consists mainly of quartz diorite,contains medium contents of SiO_2,Al_2O_3 and ALK,low Mg#,suggesting that the Yangjiawan pluton is characteristic of metaluminous high-k calc alkaline series rock.The pluton has low REE content,relatively high(La/Yb)N and LREE/HREE ratios and weak Ce negative anomaly,with strong fractionation between LREE and HREE,enrichment in large ion lithophile elements(Rb,Ba,K)and high field strength elements(Zr,Hf,Y).Low negative anomalies of Nb,Ta,Ti,P and U indicate depletion in HFSE and enrichment in LILE.LA-ICP-MS zircon U-Pb dating for the Yangjiawan pluton firstly yielded an age of 139.6±2.2Ma,which belongs to middle Yanshanian period and can represent the rock-forming age of the Yangjiawan pluton.Our study shows that the Yangjiawan pluton should be the product of early Cretaceous magmatic activity.

关 键 词：岩石地球化学 锆石U-PB定年 构造环境 杨家湾岩体 北淮阳 

分 类 号：P597.3[天文地球—地球化学] P588.122[天文地球—地质学]